Display device, image processing device, and image processing method

ABSTRACT

An image processing device includes: a gain calculation section determining a gain, on the basis of a first partial image in a first frame image that includes a process target line; and a correction section correcting pixel luminance information regarding the process target line, on the basis of the gain.

BACKGROUND

The present disclosure relates to a display device that displays animage, and an image processing device and an image processing methodthat are used in such a display device.

Recently, cathode ray tube (CRT) display devices have been increasinglyreplaced by organic electro-luminescence (EL) or liquid crystal displaydevices. Organic EL or liquid crystal display devices, as describedabove, achieve slimmer packages than those of CRT display devices,thereby decreasing their footprints easily. In addition, they exhibitlow power consumption, and are therefore advantageous in terms ofecology. Among of these display devices, in particular, organic ELdisplay devices are attracting many attentions. Since organic EL displaydevices are self-luminous devices, they make it possible to further slimdown their packages and decrease their power consumption.

For the purpose of decreasing the power consumption of display devices,as described above, many studies have been conducted. For example,Japanese Unexamined Patent Application Publication No. 2003-134418discloses a display device equipped with an automatically brightnesslimit (ABL) function, which controls the display luminance of the screenin such a way that it does not excessively increase.

SUMMARY

For display devices, in general, a high image quality is in demand. Morespecifically, it is in demand that a display device does not cause aviewer to perceive any unnatural feeling when the ABL function isactive.

It is desirable to provide a display device, an image processing device,and an image processing method, all of which enable the image quality tobe enhanced.

A display device according to an embodiment of the present disclosureincludes: a display section displaying an image by performing linesequential scanning; a gain calculation section determining a gain, onthe basis of a first partial image in a first frame image that includesa process target line; and a correction section correcting pixelluminance information regarding the process target line, on the basis ofthe gain.

An image processing device according to an embodiment of the presentdisclosure includes: a gain calculation section determining a gain, onthe basis of a first partial image in a first frame image that includesa process target line; and a correction section correcting pixelluminance information regarding the process target line, on the basis ofthe gain.

An image processing method according to an embodiment of the presentdisclosure includes: determining a gain, on the basis of a first partialimage in a first frame image that includes a process target line; andcorrecting pixel luminance information regarding the process targetline, on the basis of the gain.

In the display device, the image processing device, and the imageprocessing method according to the above-described embodiments of thepresent disclosure, the gain is determined on the basis of a frameimage, and the pixel luminance information regarding the process targetline is corrected on the basis of the gain. The gain is determined onthe basis of the first partial image in the first frame image thatincludes the process target line.

The display device, the image processing device, and the imageprocessing method according to the above-described embodiments of thepresent disclosure are configured to determine the gain on the basis ofthe first partial image in the first frame image that includes theprocess target line. Therefore, all of the display device, the imageprocessing device, and the image processing method achieve high imagequality.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary, and are intended toprovide further explanation of the technology as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the disclosure, and are incorporated in and constitutea part of this specification. The drawings illustrate embodiments and,together with the specification, serve to explain the principles of thetechnology.

FIG. 1 is a block diagram of an exemplary configuration of a displaydevice according to a first embodiment of the present disclosure.

FIG. 2 is a block diagram of an exemplary configuration of an EL displaysection of FIG. 1.

FIG. 3 is a view illustrating a general cross-section configuration ofthe EL display section of FIG. 1.

Left and right parts of FIG. 4 are explanatory views of an exemplaryoperation performed by an RGBW conversion section of FIG. 1.

FIG. 5 is an explanatory view of an exemplary operation performed by again calculation section of FIG. 1.

FIG. 6 is a diagram depicting an exemplary property of a LUT of FIG. 1.

FIG. 7 is a timing chart in an exemplary operation performed by the ELdisplay section of FIG. 1.

Parts (A), (B), and (C) of FIG. 8 are explanatory views of an exemplaryoperation performed by the display device of FIG. 1.

FIG. 9 is an explanatory view of an exemplary operation performed by theLUT of FIG. 1.

Parts (A), (B), and (C) of FIG. 10 are timing charts in anotherexemplary operation performed by the EL display section of FIG. 1.

FIG. 11 is an explanatory view of an exemplary operation performed by again calculation section according to a comparative example.

Parts (A), (B), and (C) of FIG. 12 are explanatory views of an exemplaryoperation performed by a display device according to the comparativeexample.

Parts (A), (B), and (C) of FIG. 13 are timing charts in an exemplaryoperation performed by an EL display section according to thecomparative example.

FIG. 14 is a block diagram of an exemplary configuration of an ELdisplay section according to a modification of the first embodiment.

FIG. 15 is an explanatory view of an exemplary operation performed by again calculation section according to another modification of the firstembodiment.

FIG. 16 is an explanatory view of an exemplary operation performed by again calculation section according to still another modification of thefirst embodiment.

FIG. 17 is a block diagram of an exemplary configuration of a displaydevice according to a second embodiment of the present disclosure.

FIG. 18 is an explanatory view of an exemplary operation performed by again calculation section of FIG. 17.

FIG. 19 is a diagram depicting an exemplary property of a LUT of FIG.17.

FIG. 20 is a flowchart of the exemplary operation performed by the gaincalculation section of FIG. 17.

Parts (A), (B), and (C) of FIG. 21 are explanatory views of an exemplaryoperation performed by the display device of FIG. 17.

FIG. 22 is a block diagram of an exemplary configuration of a displaydevice according to a third embodiment of the present disclosure.

FIG. 23 is a diagram depicting an exemplary property of a LUT in awhite-pixel correction section of FIG. 22.

Parts (A), (B), and (C) of FIG. 24 are explanatory views of an exemplaryoperation performed by the display device of FIG. 22.

FIG. 25 is a schematic view illustrating an appearance structure of a TVunit including any of the display devices according to the embodiments.

FIG. 26 is a block diagram of an exemplary configuration of a displaydevice according to a modification.

FIG. 27 is a block diagram of an exemplary configuration of a displaydevice according to another modification.

FIG. 28 is a block diagram of an exemplary configuration of a displaydevice according to still another modification.

FIG. 29 is a block diagram of an exemplary configuration of an ELdisplay section according to yet another modification.

DETAILED DESCRIPTION

Hereinafter, some embodiments of the present disclosure will bedescribed in detail, with reference to the accompanying drawings. Thisdescription will be given in the following order.

-   1. First embodiment-   2. Second embodiment-   3. Third embodiment-   4. Application examples    [1. First Embodiment]    (Exemplary Configuration)    (Overall Exemplary Configuration)

FIG. 1 depicts an exemplary configuration of a display device accordingto a first embodiment. A display device 1 is an EL display device thatincludes an organic EL display element as a display element. Note thatan image processing device and an image processing method according toembodiments of the present disclosure are embodied by this embodiment,and therefore a description thereof will also be given collectively. Thedisplay device 1 includes an input section 11, an image processingsection 20, and an EL display section 30.

The input section 11 serves as an input interface, and generates animage signal Sp0, on the basis of an image signal supplied from anexternal apparatus. In this example, the image signal supplied to thedisplay device 1 contains red (R) luminance information IR, green (G)luminance information IG, and blue (B) luminance information IB. Inother words, the image signal is a so-called RGB signal.

The image processing section 20 generates an image signal Sp1 and atiming control signal St by subjecting the image signal Sp0 to apredetermined image process, such as an automatically brightness limit(ABL) process as will be described later.

The EL display section 30 is a display section that includes an organicelectro-luminescence (EL) display element as a display element, andperforms a display operation, on the basis of the image signal Sp1 andthe timing control signal St.

FIG. 2 depicts an exemplary configuration of the EL display section 30.The EL display section 30 includes a pixel array section 33, a verticaldrive section 31, and a lateral drive section 32.

The pixel array section 33 has a configuration in which pixels Pix arearranged in a matrix fashion. In this example, each pixel Pix includesfour sub-pixels SPix, or red (R), green (G), blue (B), and white (W)sub-pixels SPix. In the example, the four sub-pixels SPix of each pixelPix are arranged in two rows and two columns. In more detail, in eachpixel Pix, the red (R), green (G), white (W), and blue (B) sub-pixelsSPix are arranged at the upper left, upper right, lower left, and lowerright locations, respectively.

The vertical drive section 31 generates scan signals, on the basis ofthe timing control signal St supplied from the image processing section20, and sequentially selects the sub-pixels SPix in the pixel arraysection 33 for each line by supplying the timing control signals St tothe pixel array section 33 through gate lines GCL, thereby performingline sequential scanning. The lateral drive section 32 generates pixelsignals, on the basis of the image signal Sp1 and the timing controlsignal St, and supplies the pixel signals to the pixel array section 33through data lines SGL, thereby supplying these pixel signals to theindividual sub-pixels SPix in the pixel array section 33.

FIG. 3 depicts a cross-section configuration of main part of the ELdisplay section 30. The EL display section 30 includes an EL layer 36,and color filters CFR, CFG, and CFB. In this example, the sub-pixelsSPix of the EL layer 36 are configured to emit while light fluxesindependently of one another. The color filters CFR, CFG, and CFB arefilters that allow red (R) light, green (G) light, and blue (B) light topass therethrough, respectively, and are formed on a transparentsubstrate 37 provided opposite the EL layer 36. In FIG. 2, the red (R),green (G), and blue (B) sub-pixels SPix are provided with the colorfilters CFR, CFG, and CFB, respectively. Meanwhile, the white (W)sub-pixel SPix is configured without a color filter. This configurationenables the red, green, blue, and white sub-pixels SPix to emit lightfluxes of corresponding colors.

(Image Processing Section 20)

The image processing section 20 performs an image process, such as theABL process as will be described later. This ABL process decreases thepower consumption of the pixel array section 33. For example, when thepixel array section 33 displays a complementary color (such as cyan,yellow or magenta) by using two colors out of the red (R), green (G),and blue (B), the pixel array section 33 has to cause two correspondingsub-pixels SPix to emit light. In such a case, the power consumption ofthe pixel array section 33 is prone to being increased. Therefore, theimage processing section 20 calculates an average current Aavg of thepixel array section 33, and adjusts the luminance of the pixel arraysection 33 in accordance with the average current Aavg. Hereinafter, theimage processing section 20 will be described in detail.

The image processing section 20 includes a linear gamma conversionsection 21, an RGBW conversion section 22, a gain calculation section23, a multiplication section 24, a gamma conversion section 25, and atiming control section 26.

The linear gamma conversion section 21 converts the received imagesignal Sp0 into an image signal Sp21 having a linear gamma property. Ingeneral, in the image signal supplied from an external source, the gammavalue is set to, for example, 2.2 so as to match the property of atypical display device, and therefore the image signal has a nonlineargamma property. The linear gamma conversion section 21 converts thisnonlinear gamma property into a linear gamma property, in order tofacilitate the process performed by the image processing section 20.

The RGBW conversion section 22 generates an RGBW signal, on the basis ofthe RGB signal, or the image signal Sp21, and outputs the RGBW signal asan image signal Sp22. Specifically, the RGBW conversion section 22converts the RGB signal into the RGBW signal. Here, the RGB signalcontains three pieces of luminance information, namely, red luminanceinformation IR, green luminance information IG, and blue luminanceinformation IB. Meanwhile, the RGBW signal contains four pieces ofluminance information, namely, red (R) luminance information IR2, green(G) luminance information IG2, blue (B) luminance information IB2, andwhite (W) luminance information IW2.

Left and right parts of FIG. 4 schematically depict an exemplaryoperation performed by the RGBW conversion section 22. First, the RGBWconversion section 22 determines luminance information IW2, on the basisof the minimum (the luminance information IB in this example) among thereceived red luminance information IR, green luminance information IG,and blue luminance information IB. Then, the RGBW conversion section 22determines the red (R) luminance information IR2, the green (G)luminance information IG2, and the blue (B) luminance information IB2,on the basis of the pieces of the luminance information IR, IG, and IB,respectively.

Concretely, the RGBW conversion section 22 determines the pieces ofluminance information IR2, IG2, IB2, and IW2, on the basis of thefollowing expressionsIR2=IR−Min(IR,IG,IB)×Cw  (1)IG2=IG−Min(IR,IG,IB)×Cw  (2)IB2=IB−Min(IR,IG,IB)×Cw  (3)IW2=Min(IR,IG,IB)×Cw×Lw  (4)

where: Min (IR, IG, IB) denotes the minimum among the pieces ofluminance information IR, IG, and IB; Cw denotes a constant (0≦Cw≦1);and Lw denotes a parameter that represents a ratio of the sum of therespective maximum luminances of the red, green, and blue sub-pixelsSPix to the maximum luminance of the white sub-pixel SPix.

The RGBW conversion section 22 determines the pieces of luminanceinformation IR2, IG2, IB2, and IW2, on the basis of the aboveexpressions, and outputs the RGBW signal containing the pieces ofluminance information IR2, IG2, IB2, and IW2 as the image signal Sp22.

The gain calculation section 23 calculates a gain G to be used for theABL process, on the basis of the image signal Sp22 (or the RGBW signal).The gain calculation section 23 calculates the average current Aavg forall the pixels Pix in the pixel array section 33, on the basis of theimage signal Sp22. In addition, the gain calculation section 23calculates the gain G for each line, on the basis of the average currentAavg. The gain calculation section 23 contains a look up table (LUT) 29that stores a relationship between the average current Aavg and the gainG. The gain calculation section 23 converts the average currents Aavginto the gains G through the LUT 29, as will be described later.

The multiplication section 24 individually multiplies the pieces ofluminance information IR2, IG2, IB2, and IW2 contained in the imagesignal Sp22 by the gain G calculated by the gain calculation section 23.Then, the multiplication section 24 outputs this result as an imagesignal Sp24.

FIG. 5 depicts a gain calculation operation performed by the gaincalculation section 23. Specifically, FIG. 5 depicts a process appliedto a series of received frame images F. For example, F(n−1) denotes a(n−1)th frame image F, and F(n) denotes a (n)th frame image F.

It is assumed that the gain calculation section 23 calculates the gainG, which is to be multiplied by a line L in the multiplication section24. In this case, the gain calculation section 23 calculates the averagecurrent Aavg, on the basis of the pieces of luminance information IR2,IG2, IB2, and IW2 regarding an image area (calculation target area RG).The above calculation target area RG precedes the line L, and isequivalent to an area of a single frame image. In more detail, forexample, it is assumed that the gain calculation section 23 calculatesthe gain G which is to be multiplied by a 300th line L within the frameimage F(n) in the multiplication section 24. In this case, the gaincalculation section 23 calculates the average current Aavg for thecalculation target area RG that spans between a 300th line within theframe image F(n−1) preceding the frame image F(n) and a 299th linewithin the frame image F(n).

When the gain calculation section 23 calculates the average currentAavg, it first determines a pixel current Apix for each pixel Pix withinthe calculation target area RG through the following expressionApix=IR2×KR+IG2×KG+IB2×KB+IW2×KW  (5)

where KR, KG, KB, and KW denote current ratio coefficients by which thepieces of luminance information IR2, IG2, IB2, and IW2 are convertedinto corresponding currents. Then, the gain calculation section 23calculates the average current Aavg by determining an average of pixelcurrents Apix flowing in all the pixels Pix within the calculationtarget area RG.

Followed by, the gain calculation section 23 converts the above averagecurrent Aavg into the gain G through the LUT 29.

FIG. 6 depicts a relationship between the average current Aavg and thegain G in the LUT 29. In this example, when the average current Aavg isequal to or smaller than a predetermined current Ath, the gain Gbecomes 1. Meanwhile, as the average current Aavg is increasing from thepredetermined current Ath, the gain G is gradually decreasing from 1.

In the above way, the gain calculation section 23 determines the averagecurrent Aavg of the calculation target area RG for each line L, andcalculates the gain G. Then, the multiplication section 24 individuallymultiplies the gain G by the pieces of luminance information IR2, IG2,IB2, and IW2 related to the line L. When the gain calculation section 23processes the next line L, it shifts the calculation target area RG byone line. Then, the gain calculation section 23 determines the averagecurrent Aavg of the shifted calculation target area RG, and determinesthe gain G. Moreover, the multiplication section 24 performs themultiplication process in the above manner.

The gamma conversion section 25 converts the image signal Sp24 havingthe linear gamma property into the image signal Sp1 having the nonlineargamma property corresponding to the property of the EL display section30.

The timing control section 26 generates the timing control signal St, onthe basis of the image signal Sp0, and supplies the timing controlsignal St to the EL display section 30.

Herein, the multiplication section 24 corresponds to a concrete exampleof a “correction section” according to an embodiment of the presentdisclosure. The frame image F(n) corresponds to a concrete example of a“first frame image” according to an embodiment of the presentdisclosure. The frame image F(n−1) corresponds to a concrete example ofa “second frame image” according to an embodiment of the presentdisclosure. The pieces of luminance information IR2, IG2, IB2, and IW2correspond to a concrete example of “pixel luminance information”according to an embodiment of the present disclosure.

(Operation and Effect)

Next, a description will be given of an operation and effect of thedisplay device 1 according to this embodiment.

(Outline of Overall Operation)

First, a description will be given of an outline of an overall operationperformed by the display device 1, with reference to FIG. 1 and someother drawings. The input section 11 generates the image signal Sp0, onthe basis of the image signal supplied from an external apparatus. Thelinear gamma conversion section 21 converts the received image signalSp0 into the image signal Sp21 having the linear gamma property. TheRGBW conversion section 22 generates the RGBW signal, on the basis ofthe RGB signal, or the image signal Sp21, and outputs the RGBW signal asthe image signal Sp22. The gain calculation section 23 calculates thegain G for each line L, on the basis of the image signal Sp22. Themultiplication section 24 individually multiplies the gain G by thepieces of luminance information IR2, IG2, IB2, and IW2 related to theline L which are contained in the image signal Sp22. Then, themultiplication section 24 outputs the multiplication result as the imagesignal Sp24. The gamma conversion section 25 converts the image signalSp24 having the linear gamma property into the image signal Sp1 havingthe nonlinear gamma property corresponding to the property of the ELdisplay section 30. The timing control section 26 generates the timingcontrol signal St, on the basis of the image signal Sp0. The EL displaysection 30 performs a display operation, on the basis of the imagesignal Sp1 and the timing control signal St.

(Detailed Operation)

FIG. 7 depicts the line sequential scanning performed by the displaydevice 1. In FIG. 7, a vertical axis represents a scan location in theEL display section 30 in a sequential scan direction. For example,“F(n)” denotes that the EL display section 30 performs the displayoperation based on the frame image F(n), and “OFF” denotes that the ELdisplay section 30 is in a light non-emitting state.

As illustrated in FIG. 7, the display device 1 performs line sequentialscanning in a direction from an uppermost part to a lowermost partduring each frame period, on the basis of each frame image F.Light-emitting periods P3 and light-out periods P4 alternately andrepeatedly appear on each line L. The pixel signals are written during awriting period P1 within the light-out period P4, whereas initializationand correction operations are performed during a preparation period P2within the light-out period P4. Furthermore, the pixels Pixcorresponding to the line L emit light during the light-emitting periodP3. After that, the display device 1 causes the pixels Pix to stopemitting the light, and performs a writing operation of the pixel signalfor next light emission and the initialization operation.

Next, a description will be given of the ABL process performed by thedisplay device 1. The display device 1 performs this ABL process, inorder to control the display luminance of the screen in such a way thatit does not excessively increases. With the ABL process, the powerconsumption of the display device 1 is decreased.

Parts (A) to (C) of FIG. 8 depict an exemplary operation performed bythe display device 1 during the ABL process. In more detail, Part (A)depicts frame images F entered in the display device 1, Part (B) depictsthe gain G, and Part (C) depicts display images provided by the ELdisplay section 30. FIG. 9 depicts the gain G in the individual statesof FIG. 8. In this example, as depicted in Part (A) of FIG. 8, two blackimages (or frame images F(n−2) and F(n−1)) and three white images (orframe images F(n), F(n+1), and F(n+2)) are supplied to the displaydevice 1, in this order. Here, display images D correspond to the frameimages F. For example, the display image D(n) is an image displayed as aresult of an image process applied to the frame image F(n).

When the series of frame images F are supplied to the display device 1,the gain calculation section 23 calculates the gain G for each line L,on the basis of the pieces of luminance information IR2, IG2, IB2, andIW2 (image data) regarding the calculation target area RG that precedeseach line L. Then, the multiplication section 24 individually multipliesthe gain G by the pieces of luminance information IR2, IG2, IB2, and IW2related to each line L. The EL display section 30 displays the imagesthat have been processed in this manner, as the display images D.Hereinafter, this operation will be described in detail by givingprocesses applied to lines L11 to L14 as examples.

When the pieces of luminance information IR2, IG2, IB2, and IW2regarding a line L11 within the frame image F(n−1) (see Part (A) of FIG.8) are supplied, the gain calculation section 23 determines a gain G11,on the basis of image data of the calculation target area RG thatprecedes the line L11. Since both the frame image F(n−1) and thepreceding frame image F(n−2) are black images, image data of thecalculation target area RG entirely indicate black. In this case, theaverage current Aavg of the calculation target area RG becomessufficiently low, and the gain G11 becomes “1” as depicted in FIG. 9.Consequently, black display is created on the line L11 (see Part (C) ofFIG. 8).

Furthermore, when the pieces of luminance information IR2, IG2, IB2, andIW2 regarding a line L12 within the frame image F(n) (see Part (A) ofFIG. 8) are supplied, the gain calculation section 23 similarlydetermines a gain G12, on the basis of image data of the calculationtarget area RG that precedes the line L12. Since the frame image F(n)and the preceding frame image F(n−1) are a white image and a blackimage, respectively, the gain G12 becomes “1” as depicted in FIG. 9.This is because the average current Aavg of the calculation target areaRG is larger than that of the above line L11, but is still smaller thanthe predetermined current Ath. Consequently, white display is created onthe line L12 (see Part (C) of FIG. 8).

After that, when the pieces of luminance information IR2, IG2, IB2, andIW2 regarding a line L13 within the frame image F(n)(see Part (A) ofFIG. 8) are supplied, the gain calculation section 23 similarlydetermines a gain G13, on the basis of image data of the calculationtarget area RG that precedes the line L13. In this case, the calculationtarget area RG contains a larger proportion of a white image than thatpreceding the line L12, as described above, does. Accordingly, theaverage current Aavg of the calculation target area RG becomes higher toexceed the predetermined current Ath, so that the gain G13 becomes lowerthan 1, as depicted in FIG. 9. Consequently, display in which theluminance is slightly suppressed is created on the line L13, (see Part(C) of FIG. 8).

Moreover, the pieces of luminance information IR2, IG2, IB2, and IW2regarding a line L14 within the frame image F(n+1) (see Part (A) of FIG.8) are supplied, the gain calculation section 23 similarly determines again G14, on the basis of image data of the calculation target area RGthat precedes the line L14. Since both the frame image F(n+1) and thepreceding frame image F(n) are white images, the average current Aavg ofthe calculation target area RG becomes sufficiently high, and thereforethe gain G14 becomes lower, as depicted in FIG. 9. Consequently, displayin which the luminance is suppressed even more is created on the lineL14 (see Part (C) of FIG. 8).

As described above, the display device 1 determines the gain G, on thebasis of the image data of the calculation target area RG that precedesthe line L to be processed. Therefore, the ABL process is performed in ashorter response time than a comparative example which will be describedlater.

Parts (A) to (C) of FIG. 10 depict an operation performed by the displaydevice 1 when the series of frame images F are supplied to the displaydevice 1 as described in FIG. 8. In more detail, Part (A) depicts theline sequential scanning, Part (B) depicts the gain G, and Part (C)depicts the average current Aavg of the pixel array section 33.

The line sequential scanning applied to the frame image F(n) (whiteimage) starts. When the light-emitting periods P3 successively start onthe respective lines L from a timing t1, the average current Aavggradually increases, as described in Part (C) of FIG. 10. Then, theaverage current Aavg is kept substantially constant from a timing t2 atwhich the light-emitting period P3 for an uppermost line of the ELdisplay section 30 ends.

The current based on the frame image F(n) decreases from a timing t3 atwhich the light-emitting period P3 for a lowermost line of the ELdisplay section 30 starts. However, the line sequential scanning appliedto the next frame image F(n+1) (white image) starts at the timing t3.Accordingly, a current based on the frame image F(n+1) increases.Consequently, the average current Aavg is kept substantially constanteven after the timing t3.

The gain G gradually decreases over a period from the timing t1 to thetiming t3 (see Part (B) of FIG. 10), as described with reference toFIGS. 8 and 9. Therefore, an increase in the average current Aavg overthe period from the timing t1 to the timing t3 is suppressed as comparedwith the comparative example which will be described later.Consequently, the average current Aavg, or the current consumption, isdecreased.

COMPARATIVE EXAMPLE

Next, a description will be given of an effect provided by thisembodiment, in comparison with the comparative example. This comparativeexample constitutes a display device 1R including a gain calculationsection 23R that determines the gain G, on the basis of the precedingframe image F. Other configurations of the comparative example aresubstantially the same as those of this embodiment (see FIG. 1).

FIG. 11 depicts an operation in which the gain calculation section 23Raccording to this comparative example calculates the average currentAavg. When the gain calculation section 23R calculates the gain G whichis to be multiplied by the line L in the multiplication section 24, itcalculates the average current Aavg, on the basis of the pieces ofluminance information IR2, IG2, IB2, and IW2 regarding the frame imageF(n−1) that precedes the frame image F containing the line L. Then, thegain calculation section 23R determines the gain G, on the basis of theaverage current Aavg. Specifically, the gain calculation section 23Rcalculates the gain G for each frame image F. Furthermore, themultiplication section 24 individually multiplies the gain G by all thepieces of luminance information IR2, IG2, IB2, and IW2 regarding theframe image F(n).

Parts (A) to (C) of FIG. 12 depict an exemplary operation performed bythe display device 1R during the ABL process. In more detail, Part (A)depicts the frame images F entered in the display device 1R, Part (B)depicts the gain G, and Part (C) depicts the display images D providedby the EL display section 30.

To give an example, as for a gain G15R for a line L15R within the frameimage F(n−1), it becomes “1.” This is because the preceding frame imageF(n−2) is a black image, and the average current Aavg becomessufficiently low. Consequently, black display is created on the lineL15R (Part (C) of FIG. 12).

To give another example, as for a gain G16R for a line L16R within theframe image F(n), it becomes “1.” This is because the preceding frameimage F(n−1) is a black image, and the average current Aavg becomessufficiently low. Consequently, white display is created on the lineL16R (Part (C) of FIG. 12).

To give still another example, as for a gain G17R for a line L17R withinthe frame image F(n+1), it becomes sufficiently low. This is because thepreceding frame image F(n) is a white image, and the average currentAavg becomes sufficiently high. Consequently, display in which theluminance is suppressed is created on the line L17R (Part (C) of FIG.12).

As described above, the display device 1R determines the gain G, on thebasis of the preceding frame image F. Accordingly, throughout everyframe image F, the gain G is uniform independently of the lines L, asdepicted in Part (B) of FIG. 12. Thus, in the case where the suppliedimage is changed from a black image to a white image, a single imagewith high luminance (display image D(n)) may be displayed, as depictedin Part (C) of FIG. 12.

Parts (A) to (C) of FIG. 13 depict an operation performed by the displaydevice 1R when a series of frame images F, as described above, aresupplied to the display device 1R. In more detail, Part (A) depicts theline sequential scanning, Part (B) depicts the gain G, and Part (C)depicts the average current Aavg of the pixel array section 33.

The line sequential scanning applied to the frame image F(n)(whiteimage) starts, and when the light-emitting periods P3 successivelystarts on the corresponding lines L from the timing t1, the averagecurrent Aavg gradually increases, as depicted in Part (C) of FIG. 10. Inthis case, the average current Aavg further increases, as opposed tothis embodiment (see FIG. 10), because the gain G is kept atapproximately “1.” Then, this high average current Aavg is keptsubstantially constant from the timing t2. Moreover, with the decreasein the gain G, the average current Aavg becomes substantially the sameas that of this embodiment (Part (C) of FIG. 10), at the timing t3, andis kept constant from the timing t3, as depicted in Part (B) of FIG. 13.Thus, in the display device 1R, the average current Aavg may transientlyincrease (for example, within the period from the timing t2 to thetiming t3).

As described above, the display device 1R according to the comparativeexample determines the gain G, on the basis of the preceding frame imageF. Accordingly, the response of the display device 1R to the change inthe frame image F may be delayed. In this case, the white image would betransiently displayed, as depicted in FIG. 12. Thus, the display device1R may have a risk of lowering the image quality.

As described above, since it is difficult for the display device 1R torespond to the change in the frame image F quickly, the average currentAavg may transiently increase, as depicted in FIG. 13. In order to avoidsuch a disadvantage, a power supply device equipped with a highcurrent-supply capacity which is capable of supplying a large current isnecessary. In many cases, such a power supply device consumes a largecurrent by itself, and is large in size. If the power supply deviceconsumes a large current, it may negate a feature of an organic ELdisplay device which is its low power consumption. Furthermore, thepower supply device is large in size, the display device may also beenlarged. In this case, another feature of an organic EL display devicewhich is its small footprint may be negated. Moreover, the designflexibility of an organic EL display device may be decreased, therebylowering the product competitiveness.

A method of installing a frame memory is conceivable as a method ofreducing the risk that the average current Aavg transiently increases,as described above. Specifically, a method is conceivable, in which:data of each frame image is temporally stored in a frame memory; thegain G is determined on the basis of the data; and each frame image isprocessed by using the gain G and is displayed. However, employing thismethod may cause the timing of the display image to be delayed. Forexample, in the case where the above method is applied to a game inwhich the image is changed quickly, the timing of the display image mayfail to follow a user's operation promptly. As a result, the operabilityof the game would be deteriorated.

In contrast, the display device 1 according to this embodimentdetermines the gain G, on the basis of image data within the calculationtarget area RG that precedes the line L. This configuration increasesthe speed of the response to the change in the frame image F. Thus, itis possible to reduce the risk of transiently displaying the white imageas depicted in FIG. 8, thereby reducing the risk of lowering the imagequality.

The quick response to the change in the frame image F, as describedabove, also reduces the risk of transiently increasing the averagecurrent Aavg, as depicted in FIG. 10. This makes it possible to lessenthe current-supply capacity requested for the power supply device, thusdecreasing the current consumption of the display device 1 andincreasing the design flexibility thereof. In addition, the installationof a frame memory becomes unnecessary, thus reducing a risk of causing aviewer to perceive any unnatural feeling even in game applications orthe like.

[Effect]

In this embodiment, as described above, the gain is determined on thebasis of image data within a calculation target area that precedes aline to be processed. Therefore, it is possible to decrease the currentconsumption and increase the design flexibility.

(Modification 1-1)

In the above first embodiment, the pixel array section 33 of the ELdisplay section 30 has the pixels Pix, each of which is provided withthe four sub-pixels SPix arranged in the two rows and the two columns.However, there is no limitation on the arrangement of the sub-pixelsSPix. Alternatively, each pixel Pix may be configured by aligning thefour sub-pixels SPix so as to extend in a vertical direction Y andarranging these aligned sub-pixels SPix side by side in a lateraldirection X, for example, as illustrated in FIG. 14. In this example,red (R), green (G), blue (B), and white (W) sub-pixels SPix are arrangedin each pixel Pix, in this order from the left.

(Modification 1-2)

In the above first embodiment, the average current Aavg is determined onthe basis of all the pieces of luminance information IR2, IG2, IB2, andIW2 regarding the calculation target area RG that precedes the line L.However, there is no limitation on the method of determining the averagecurrent Aavg. Alternatively, the average current Aavg may be determinedon the basis of the fewer pieces of luminance information IR2, IG2, IB2,and IW2, which are obtained by thinning out all pieces of luminanceinformation regarding the calculation target area RG. With thisalternative method, the load of the computing process is lightened.

(Modification 1-3)

In the above first embodiment, the gain calculation section 23determines the gain G, on the basis of the pieces of luminanceinformation IR2, IG2, IB2, and IW2 regarding the image area (or thecalculation target area RG) that precedes the line L and that isequivalent to an area of a single frame image. However, there is nolimitation on the method of determining the gain G. Hereinafter, someexamples of alternative methods will be described.

FIG. 15 depicts a gain calculation operation performed by a gaincalculation section 23A according to this modification. It is assumedthat the gain calculation section 23A calculates the gain G which is tobe multiplied by the line L in the multiplication section 24. In thiscase, the gain calculation section 23A determines, in the image area (orthe calculation target area RG) that precedes that line L and that isequivalent to an area of a single frame image, a gain G1 from part ofthe calculation target area RG which corresponds to the frame image Fcontaining that line L. Also, the gain calculation section 23Adetermines a gain G2 from part of the calculation target area RG whichis included in the preceding frame image F. In more detail, for example,it is assumed that the gain calculation section 23A calculates the gainG which is to be multiplied by a 300th line L within the frame imageF(n). In this case, the gain calculation section 23A determines the gainG1, on the basis of a calculation target area RG1 spanning from a 1stline to a 299th line within the frame image F(n). Also, the gaincalculation section 23A determines the gain G2, on the basis of acalculation target area RG2 spanning from a 300th line to a last linewithin the frame image F(n−1) which precedes the frame image F(n).Further, the gain calculation section 23A supplies the smaller one ofthe gains G1 and G2 to the multiplication section 24, as the gain G.Even this modification also makes it possible to produce substantiallythe same effect as the above first embodiment does.

FIG. 16 depicts a gain calculation operation performed by another gaincalculation section 23B according to this modification. It is assumedthat the gain calculation section 23B calculates the gain G which is tobe multiplied by the line L in the multiplication section 24. In thiscase, the gain calculation section 23B calculates the gain G, on thebasis of the pieces of luminance information IR2, IG2, IB2, and IW2within the calculation target area RG1 that spans from a 1st line to aline preceding the line L within the frame image F containing the lineL. Even this modification also makes it possible to producesubstantially the same effect as the above first embodiment does.

Moreover, for example, the gain calculation section 23B may calculatethe average current Aavg, on the basis of the pieces of luminanceinformation IR2, IG2, IB2, and IW2 within an image area that precedesthe line L and that is equivalent to multiple frame images.

[2. Second Embodiment]

Next, a display device 2 according to a second embodiment will bedescribed. This embodiment includes a gain calculation section 43 thatdetermines the gain G through a plurality of LUTs. Other configurationsof this embodiment are substantially the same as those of the abovefirst embodiment. Note that the same reference numerals are assigned tosubstantially the same components as those of the above firstembodiment, and a description thereof will be omitted as appropriate.

FIG. 17 illustrates an exemplary configuration of the display device 2according to this embodiment. The display device 2 includes an imageprocessing section 40. The image processing section 40 includes a gaincalculation section 43 that has two LUTs 48 and 49. The LUT 48 is usedto convert an average current Aavg3 into a gain G3, and the LUT 49 isused to convert an average current Aavg4 into a gain G4, as will bedescribed later.

FIG. 18 depicts a gain calculation operation performed by the gaincalculation section 43. It is assumed that the gain calculation section43 calculates the gain G which is to be multiplied by the line L in themultiplication section 24. In this case, the gain calculation section 43determines the gain G3, on the basis of the pieces of luminanceinformation IR2, IG2, IB2, and IW2 regarding the calculation target areaRG1 that spans from the 1st line to the preceding line within the frameimage F containing the line L. In addition, the gain calculation section43 determines the gain G4, on the basis of the preceding frame image F.In more detail, for example, it is assumed that the gain calculationsection 43 calculates the gain G which is to be multiplied by a 300thline L within the frame image F(n). In this case, the gain calculationsection 43 determines the gain G3, by calculating the average currentAavg3 on the basis of the calculation target area RG1 spanning from a1st line to a 299th line within the frame image F(n). Then, the gaincalculation section 43 determines the gain G4, by calculating theaverage current Aavg4 on the basis of the frame image F(n−1) whichprecedes the frame image F(n).

FIG. 19 depicts a relationship between the average current Aavg3 and thegain G3 in the LUT 48 and a relationship between the average currentAavg4 and the gain G4 in the LUT 49. In this example, the LUT 48exhibits substantially the same property as the LUT 29 according to theabove first embodiment (see FIG. 6) does. Meanwhile, the LUT 49 has aproperty in which the average current Aavg4 increases as the gain G4increases, as depicted in FIG. 19.

FIG. 20 depicts an exemplary operation performed by the gain calculationsection 43. Specifically, FIG. 20 depicts an operation of calculatingthe gain G for a frame image F(k) to be processed.

At Step S1, first, the gain calculation section 43 calculates theaverage current Aavg4, on the basis of a preceding frame image F(k−1),and converts the average current Aavg4 into the gain G4 through the LUT49.

At Step S2, the gain calculation section 43 determines whether or notthe average current Aavg4 is smaller than a predetermined current Ath2.If the average current Aavg4 is smaller than the predetermined currentAth2 (“Y” at Step S2), the gain calculation section 43 proceeds to aprocess at Step S3. Otherwise, if the average current Aavg4 is equal toor larger than the predetermined current Ath2 (“N” at Step S2), the gaincalculation section 43 proceeds to a process at Step S9.

If the average current Aavg4 is smaller than the predetermined currentAth2 at Step S2, the gain calculation section 43 performs processes atSteps S3 to S7 in this order for each line L.

At Step S3, first, the gain calculation section 43 outputs the gain G4as the gain G. Then, the multiplication section 24 performs amultiplication process, on the basis of the gain G.

At Step S4, the gain calculation section 43 calculates the averagecurrent Aavg3, on the basis of the calculation target area RG1corresponding to the line L to be processed, and converts the averagecurrent Aavg3 into the gain G3 through the LUT 48.

At Step S5, the gain calculation section 43 determines whether anexpression “G4<G3+α” is satisfied or not. In this expression, a denotesa predetermined value. If this expression is satisfied (“Y” at Step S5),the gain calculation section 43 proceeds to a process at Step S6.Otherwise, if the relationship is not satisfied (“N” at Step S5), thegain calculation section 43 proceeds to a process at Step S9.

At Step S6, the gain calculation section 43 determines whether or notthe above processing has been applied to all the lines L within theframe image F(k). If the processing has not yet been applied to all thelines L (“N” at Step S6), the gain calculation section 43 proceeds to aprocess at Step S7. Otherwise, if the processing has been alreadyapplied to all the lines L (“Y” at Step S6), the gain calculationsection 43 terminates this processing flow.

At Step S7, the gain calculation section 43 sets the next line L as aprocess target. Then, the gain calculation section 43 returns to theprocess at Step S3.

If the expression is not satisfied at Step S5 (“N” at Step S5), the gaincalculation section 43 determines the gain G for each of all theremaining lines L within the frame image F(k), on the basis of thecalculation target area RG1, at Step S9. In more detail, the gaincalculation section 43 calculates the average current Aavg3 for eachline L to be processed, on the basis of the calculation target area RG1.Then, the gain calculation section 43 converts the average current Aavg3into the gain G3 through the LUT 48, outputting the gain G3 as the gainG.

Through the above steps, this processing flow ends.

Parts (A) to (C) of FIG. 21 depict an exemplary operation performed bythe display device 2 during the ABL process. In more detail, Part (A)depicts the frame images F entered in the display device 2, Part (B)depicts the gain G, and Part (C) depicts display images D provided bythe EL display section 30.

When the frame image F(n−1) is supplied, the gain calculation section 43starts an operation based on the processing flow as depicted in FIG. 20.In this example, the average current Aavg4 becomes sufficiently low,because the preceding frame image F(n−2) is a black image. Accordingly,the average current Aavg4 becomes smaller than the predetermined currentAth2 (Step S2). As a result, the gain calculation section 43 proceeds tothe loop process at Steps S3 to S7. In this case, since the image in thecalculation target area RG1 is also a black image, the gain G3 becomeshigh. However, it is possible for the gain calculation section 43 toprevent the expression at Step S5 from being satisfied, by setting thepredetermined vale α appropriately. As a result, the gain calculationsection 43 proceeds to the process at Step S9. At Step S9, the gaincalculation section 43 calculates the gain G for each line L, and thegain G becomes constant.

Furthermore, when the frame image F(n) is supplied, the gain calculationsection 43 starts an operation based on the processing flow as depictedin FIG. 20. In this example, the average current Aavg4 becomessufficiently low, because the preceding frame image F(n−1) is a blackimage. Therefore, the gain G4 also becomes sufficiently low, as depictedin FIG. 19. In this case, the gain G3 becomes low, because the image inthe calculation target area RG1 is a white image. Accordingly, if theexpression at Step S5 is satisfied, the gain calculation section 43performs the loop process at Steps S3 to S7. In the loop process atSteps S3 to S7, the gain calculation section 43 outputs the gain G4 foreach of multiple lines L to be processed, as the gain G (Step S3). As aresult, the gain G for each of the multiple lines L to which the loopprocess at Steps S3 to S7 has been applied becomes constant and low, asin part W1 of FIG. 12. After performing this loop process, the gaincalculation section 43 calculates the gain G for each line L. Thecalculated gain G gradually increases, as in part W2 of FIG. 12.

As described above, the display device 2 determines the gains G3 and G4from the current frame image F(n) and the preceding frame image F(n−1),respectively, and compares the gains G3 and G4. Therefore, immediatelyafter the supplied frame image F(n) is changed from a black image to awhite image, the display device 2 first decreases the gain G, and thengradually approaches the gain G to a desired gain. This processingenables the image quality to be enhanced. Specifically, for example, inthe display device 1 according to the first embodiment, as describedabove, the gain G becomes slightly high, immediately after the suppliedframe image F(n) is changed from a black image to a white image, asdepicted in FIG. 8. This may cause a viewer to perceive unnaturalfeeling. In contrast, the display device 2 according to this embodimentoperates to first decrease the gain G immediately after the frame imageF(n) is changed from a black image to a white image, and then graduallyapproach the gain G to a desired gain, as depicted in FIG. 21. Thisprocessing prevents a viewer from perceiving unnatural feeling, therebyenabling the image quality to be enhanced.

As described above, the display device 2 determines respective gainsfrom a current frame image and a preceding frame image, and comparesboth frame images. This configuration reduces the risk of causing aviewer to feel any unnatural feeling, thus enabling the image quality tobe enhanced. Other effects produced by the second embodiment are thesame as those produced by the above first embodiment.

(Modification 2-1)

The modifications 1-1 and 1-2 of the above first embodiment may beapplied to the display device 2 of the above second embodiment.

[3. Third Embodiment]

Next, a display device 3 according to a third embodiment will bedescribed. The third embodiment includes a white-pixel correctionsection that corrects luminance of each white sub-pixel SPix on thebasis of the gain G. Other configurations of this embodiment aresubstantially the same as those of the above first embodiment. Note thatthe same reference numerals are assigned to substantially the samecomponents as those of the display device 1 according to the above firstembodiment, and a description thereof will be omitted as appropriate.

FIG. 22 depicts an exemplary configuration of a display device 3according to this embodiment. The display device 3 includes an imageprocessing section 50 that includes a gain calculation section 53 and awhite-pixel correction section 55.

The gain calculation section 53 calculates average current Aavg of thecalculation target area RG, and determines the gain G through a LUT 59,on the basis of the calculated average current Aavg, similar to the gaincalculation section 23 according to the above first embodiment.

The white-pixel correction section 55 corrects only the luminanceinformation IW2 among the pieces of luminance information IR2, IG2, IB2,and IW2 contained in the image signal Sp24, on the basis of the gain G.In addition, the white-pixel correction section 55 outputs the correctedluminance information IW2 together with the other pieces of luminanceinformation IR2, IG2, and IB2, as an image signal Sp25. The white-pixelcorrection section 55 has a LUT 56 used to correct the luminanceinformation IW2. Specifically, the LUT 56 is used to obtain a correctionamount AI for the luminance information IW2, on the basis of the gain G.

FIG. 23 depicts a relationship between the gain G and the correctionamount AI in the LUT 56. In this example, as the gain G increases, thecorrection amount ΔI decreases.

Parts (A) to (C) of FIG. 24 depict an exemplary operation performed bythe display device 3. In more detail, Part (A) depicts the pieces ofluminance information IR2, IG2, IB2, and IW2 before the multiplicationsection 24 performs the multiplication process, Part (B) depicts thepieces of luminance information IR2, IG2, IB2, and IW2 after themultiplication section 24 performs the multiplication process, and Part(C) depicts the pieces of luminance information IR2, IG2, IB2, and IW2after the white-pixel correction section 55 performs the correctionprocess.

In this example, the multiplication section 24 first individuallymultiplies the pieces of luminance information IR2, IG2, IB2 (“0” inthis example), and IW2 as depicted in Part (A) of FIG. 24 by the gain Gof 1 or lower (see Part (B) of FIG. 24). Then, the white-pixelcorrection section 55 corrects the luminance information IW2 regardingthe white sub-pixel SPix, which is one of the pieces of resultantluminance information IR2, IG2, IB2, and IW2, so as to increase by thecorrection amount ΔI. Thus, the white-pixel correction section 55increases the luminance information IW2 by the decrease in the luminancewhich is caused through the multiplication process of the multiplicationsection 24.

As described above, the display device 3 uniformly decreases the piecesof luminance information IR2, IG2, IB2, and IW2 by using the gain G, andthen increases the luminance information IW2 by the decrease in theluminance. This configuration decreases the power consumption.Specifically, since the white (W) sub-pixel SPix has no color filter, asdepicted in FIG. 3, it exhibits a higher light emitting efficiency thanthe red (R), green (G), and blue (B) sub-pixel SPix with a color filterdoes. Therefore, the display device 3 decreases the power consumption bysubstituting the light emitted from the white (W) sub-pixel SPix for thelight emitted from the red (R), green (G), and blue (B) sub-pixels SPix.Note that the balance of the luminances of the red light, green light,and blue light may be slightly changed, as depicted in Parts (A) and (C)of FIG. 24. Accordingly, preferably, the gain calculation section 53 andthe white-pixel correction section 55 may operate to the extent that theabove change does not affect the image quality.

In the above way, this embodiment corrects the luminance informationIW2, on the basis of the gain G, thereby decreasing the powerconsumption. Other effects produced by this embodiment are substantiallythe same as those produced by the above first embodiment.

[4. Application Examples]

Next, a description will be given of application examples of the displaydevices that have been described in the above embodiments andmodifications thereof.

FIG. 25 illustrates an appearance of a TV unit that includes any of thedisplay devices according to the above embodiments and the like. This TVunit is provided with, for example, an image display screen section 510that includes a front panel 511 and a filter glass 512. The TV unitincludes any of the display devices according to the above embodimentsand the like.

The display devices according to the above embodiments and the like areapplicable to electronic apparatuses of various fields, includingdigital cameras, notebook personal computers, portable terminal devicessuch as portable phones, portable game machines, and video cameras, inaddition to TV units as described above. In other words, the displaydevices according to the above embodiments and the like are applicableto electronic apparatuses of various fields which display an image.

Up to this point, the present technology has been described by givingthe embodiments, modifications thereof, and the application examples toelectronic apparatuses. However, the present technology is not limitedto the above embodiments and the like, and various modifications thereofmay be contemplated.

In the above embodiments and the like, for example, the gain calculationsection 23 determines the gain G, on the basis of the image signal Sp22output from the RGBW conversion section 22. However, there is nolimitation on a configuration of determining the gain G. Alternatively,the gain G may be determined on the basis of the image signal Sp21output from the linear gamma conversion section 21, for example, asdepicted in FIG. 26. Furthermore, the gain G may be determined on thebasis of the image signal Sp0 output from the input section 11, forexample, as depicted in FIG. 27.

In the above embodiments and the like, the multiplication section 24 isdisposed downstream of the RGBW conversion section 22. However, there isno limitation on an arrangement order of these components.Alternatively, the multiplication section 24 may be disposed upstream ofthe RGBW conversion section 22, for example, as depicted in FIG. 28. Inthis case, the gain calculation section 23 may determine the gain G, forexample, on the basis of the image signal Sp21 output from the lineargamma conversion section 21.

In the first and second embodiments and the like, each pixel Pixincludes four sub-pixels SPix, or the red (R), green (G), blue (B), andwhite (W) sub-pixels SPix. However, there is no limitation on theconfiguration of each pixel Pix. Alternatively, each sub-pixel SPix mayinclude three sub-pixels SPix, or red (R), green (G), blue (B)sub-pixels SPix, for example, as depicted in FIG. 29.

In the above embodiments and the like, the techniques are applied to ELdisplay devices. However, there is no limitation on the applications ofthe above techniques. Alternatively, for example, the techniques may beapplied to liquid crystal display devices.

Furthermore, the technology encompasses any possible combination of someor all of the various embodiments described herein and incorporatedherein.

It is possible to achieve at least the following configurations from theabove-described example embodiments of the disclosure.

-   (1) A display device, including:

a display section displaying an image by performing line sequentialscanning;

a gain calculation section determining a gain, on the basis of a firstpartial image in a first frame image that includes a process targetline; and

a correction section correcting pixel luminance information regardingthe process target line, on the basis of the gain.

-   (2) The display device according to (1), wherein the gain    calculation section determines the gain, on the basis of, in    addition to the first partial image, a second partial image in a    second frame image, the second frame image preceding the first frame    image.-   (3) The display device according to (2), wherein

the first partial image is located in a location that precedes theprocess target line in the first frame image,

the second partial image is located in an end portion of the secondframe image, and

a sum of the number of pieces of pixel luminance information regardingthe first partial image and the number of pieces of pixel luminanceinformation regarding the second partial image is equal to the number ofpieces of pixel luminance information regarding each frame image.

-   (4) The display device according to (2) or (3), wherein the gain    calculation section determines an average current to be consumed    when the display section displays the first partial image and the    second partial image, and decreases the gain as the average current    increases.-   (5) The display device according to (4), wherein the gain    calculation section determines the average current by thinning out    respective pieces of pixel luminance information regarding the first    partial image and the second partial image.-   (6) The display device according to (1), wherein

the gain calculation section determines a first gain portion on thebasis of the first partial image and a second gain portion on the basisof a second partial image in a second frame image, the second frameimage preceding the first frame image, and

the gain calculation section determines the gain, on the basis of thefirst gain portion and the second gain portion.

-   (7) The display device according to (6), wherein

the gain calculation section determines a first average current to beconsumed when the display section displays the first partial image, anddecreases the first gain portion as the first average current increases,and

the gain calculation section determines a second average current to beconsumed when the display section displays the second partial image, anddecreases the second gain portion as the second average currentincreases.

-   (8) The display device according to (6) or (7), wherein the gain    calculation section sets the gain to a smaller one of the first gain    portion and the second gain portion.-   (9) The display device according to (1), wherein the gain    calculation section determines an average current to be consumed    when the display section displays the first partial image, and    decreases the gain as the average current increases.-   (10) The display device according to (1), wherein

the gain calculation section determines a first gain portion on thebasis of the first partial image and a third gain portion on the basisof an entire second frame image, the second frame image preceding thefirst frame image, and

the gain calculation section determines the gain, on the basis of thefirst gain portion and the third gain portion.

-   (11) The display device according to (10), wherein

the gain calculation section determines a first average current to beconsumed when the display section displays the first partial image, anddecreases the first gain portion as the first average current increases,and

the gain calculation section determines a third average current to beconsumed when the display section displays the second frame image, andincreases the third gain portion as the third average current increases.

-   (12) The display device according to (10) or (11), wherein the gain    calculation section makes a comparison between the first gain    portion and the third gain portion, and sets the gain to the first    gain portion or the third gain portion, in accordance with a result    of the comparison.-   (13) The display device according to any one of (1) to (12), wherein

the display section includes a plurality of display pixels, and

each of the display pixels includes a first sub-pixel, a secondsub-pixel, a third sub-pixel, and a fourth sub-pixel, the firstsub-pixel, the second sub-pixel, and the third sub-pixel correspondingto respective wavelengths that are different from one another, and thefourth sub-pixel emitting color light of a color that is different froma color of color light which the first sub-pixel emits, a color of colorlight which the second sub-pixel emits, and a color of color light whichthe third sub-pixel emits.

-   (14) The display device according to (13), wherein

the pixel luminance information is luminance information regarding eachof the sub-pixels, and

the correction section increases the respective pieces of pixelluminance information regarding the first sub-pixel, the secondsub-pixel, the third sub-pixel, and the fourth sub-pixel in the processtarget line, as the gain increases.

-   (15) The display device according to (14), wherein the correction    section increases the pixel luminance information regarding the    fourth sub-pixel in the process target line, as the gain decreases.-   (16) The display device according to any one of (13) to (15),    wherein the first sub-pixel, the second sub-pixel, the third    sub-pixel, and the fourth sub-pixel emit the red color light, the    green color light, the blue color light, and the white color light,    respectively.-   (17) An image processing device, including:

a gain calculation section determining a gain, on the basis of a firstpartial image in a first frame image that includes a process targetline; and

a correction section correcting pixel luminance information regardingthe process target line, on the basis of the gain.

-   (18) An image processing method, including:

determining a gain, on the basis of a first partial image in a firstframe image that includes a process target line; and

correcting pixel luminance information regarding the process targetline, on the basis of the gain.

The present disclosure contains subject matter related to that disclosedin Japanese Priority Patent Application JP 2012-164332 filed in theJapan Patent Office on Jul. 25, 2012, the entire content of which ishereby incorporated by reference.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

What is claimed is:
 1. A display device, comprising: a display sectiondisplaying an image by performing line sequential scanning; a gaincalculation section determining a gain for each line, on the basis of afirst partial image in a first frame image that includes a processtarget line, the first partial image being located in a location thatprecedes the process target line in a scanning direction of the firstframe image; and a correction section correcting pixel luminanceinformation regarding the process target line, on the basis of the gain,wherein the gain calculation section determines a first gain portion onthe basis of the first partial image and a third gain portion on thebasis of an entire second frame image, the second frame image precedingthe first frame image, the gain calculation section determines the gain,on the basis of the first gain portion and the third gain portion, andthe gain calculation section makes a comparison between the first gainportion and the third gain portion, and sets the gain to the first gainportion or the third gain portion, in accordance with a result of thecomparison.
 2. The display device according to claim 1, wherein thedisplay section includes a plurality of display pixels, and each of thedisplay pixels includes a first sub-pixel, a second sub-pixel, a thirdsub-pixel, and a fourth sub-pixel, the first sub-pixel, the secondsub-pixel, and the third sub-pixel corresponding to respectivewavelengths that are different from one another, and the fourthsub-pixel emitting color light of a color that is different from a colorof color light which the first sub-pixel emits, a color of color lightwhich the second sub-pixel emits, and a color of color light which thethird sub-pixel emits.
 3. The display device according to claim 2,wherein the pixel luminance information is luminance informationregarding each of the sub-pixels, and the correction section increasesthe respective pieces of pixel luminance information regarding the firstsub-pixel, the second sub-pixel, the third sub-pixel, and the fourthsub-pixel in the process target line, as the gain increases.
 4. Thedisplay device according to claim 2, wherein the first sub-pixel, thesecond sub-pixel, the third sub-pixel, and the fourth sub-pixel emit thered color light, the green color light, the blue color light, and thewhite color light, respectively.